During the medical treatment of some patients, it becomes necessary for a patient to undergo enteric therapy by receiving fluid nutrient or medical preparations through a flexible feeding tube having a very small cross-sectional diameter. Feeding tubes are inserted either orally or nasally, the tube passing through the esophagus and resting within the patient's stomach or duodenum. Typically, feeding tubes are necessary for patients who are unable to swallow or have difficulty masticating, but nevertheless have functional gastrointestinal tracts. An essential component in enteric therapy for use in combination with a feeding tube is a distensible feeding bag to contain a selected quantity of fluid. Generally, a feeding bag is suspended from an upright frame or hanger to permit gravity feeding of the fluid contained within the bag.
Prior art feeding bags generally have an outlet positioned along the bottom edge of the bag into which the proximal end of a feeding tube administration apparatus is inserted. Such apparatuses generally include a segment of administration tubing having a cross-sectional diameter greater than the feeding tube, a drip chamber interposed along the length of the administration tube and a connector to join the administration tube to the feeding tube.
The rate of flow of fluid from the feeding bag into the feeding tube is usually controlled and limited by securing a tube set clamp, of either a roller or screw type, onto the administration tube. Such clamping permits adjustment of the rate of fluid flow according to the physician's specification. A problem with prior art enteric feeding bags occurs if the set clamp is improperly adjusted or if the clamp becomes disengaged entirely resulting in an uncontrolled rate of fluid input to the patient. High rates of flow cause inundation or "bolus" feeding with the obvious adverse effect of the patient receiving an entire supply of fluid contained within the bag over a short period of time. The amount of fluid received by a patient in bolus feeding may be significant since many standard enteric feeding bags may be 1,000 milliliters in volume or more. Hence, a need existed for an enteric feeding bag which by design can limit the amount of fluid dispensed.
Moreover, if a health care attendant is not present to disengage a prior art feeding bag at the conclusion of a feeding period, the bag will become totally void of fluid and the patient will begin to ingest air or vapor remaining within the bag. Hence, a need also existed for an enteric feeding bag which will automatically cease feeding fluid to a patient thereby preventing ingestion of air upon total fluid evacuation of the bag.
Finally, prior art distensible feeding bags often incur problems with constant flow rates from the bags resulting from configurational distortion of the peripheral edges of the bags from both the weight and volume of fluid contained within the bag. A need therefore existed for an enteric feeding bag which continues to maintain its peripheral configuration irrespective of the amount of fluid contained therein.